Support for block variation JS generation

[bacoords]

This tool generates the JS object for creating blocks with inner blocks where it expects arrays/separate parameters (where you have name, attributes, innerBlocks separately).

But for Block Variations, it's basically an object with 'name' and 'innerBlocks' as keys in the object. If PRs are being reviewed still, let me know.

InnerBlocks

[
	'core/group',
	{
		"layout":{
			"type":"constrained"
		}
	},
	[
		[
			'core/paragraph',
			{},
			[]
		],
		
	]
],

would be more like

Block Variation

{
	name: 'core/group',
	attributes: {
		"layout":{
			"type":"constrained"
		}
	},
	innerBlocks: [
		{
			name: 'core/paragraph',
			attributes: {},
			innerBlocks: []
		},
		
	]
},